Antenna system



June 9, 1953 s. M. DoDlNG'roN 2,641,755

ANTENNA SYSTEM Filed March 26, 1945 I N V EN TOR. 5l/EN H. M. 00a/Graw ATZURZ'Y Patented June 9, v1953 UNITED STATES PATENT OFFICE ,y

, t l 2,641,756 j y ,ANTENNA SYSTEM Sven H. M.' .'Do'dington, Forest Hills, N. Y., assignor to Federal Telephone and Radio Corporation, Newark, N. J., a corporation of Delaware fApplication March 26, 1943, Serial No. 480,604

This invention relates to radio antennas and in particular to antennas suitable for use with impulse repeaters.

` An` object of the invention is -to devise an antenna system suitable for intercepting electromagnetic waves regardless of the polarization of ceiving apparatus.

Still another object of the invention is to devise an antenna and oscillation generating system suitable for use with pulse repeater systems such as disclosed in my copending application entitled Pulse Repeatersff filed March 2,6, 1943,

and bearing Serial Q Number 489,603.

The abv'eland'other objects and features of my invention will become more apparent upon considerationof the following descriptionto be read in connection with the accompanying drawings in which: e y

Fig. 1 illustrates in perspective `an antenna system and self contained oscillator for simultane- .ously radiating bo-th horizontally and vertically polarided waves, and

Fig. 2 represents in perspective a modification of the embodiment illustrated in Fig. 1 wherein the horizontal radiator comprises crossed dipole antennas.

Disclosed in my above mentioned copending application is a pulse repeater system primarily adapted to give false indications to an enemy who is attempting to ascertain the location of ships, aircraft, etc., by means of reilected radio waves. A more complete description of a system of this character is disclosed in a copending application of E. M. Deloraine and H. G. Busignies, Serial No. 436,846, filed March 30, 1942.

In systems of this type, the impulse repeater apparatus is suspended from a balloon during the period in which it is in operation. It is necessary that the equipment be self-contained and house all of the operating parts together with Va suitable power supply. All adjustments are made prior to the time the balloon is to be released.

Referring now to Fig. 1 the reference character a claims. (Cl. 343-100) in a common plane and with the extremities of the members positioned adjacent eachother. For example, the extremities 8 and I0 of member 4 are positioned adjacent the extremities I 2 and I4, respectively, of member 6.

The electrical length of the'members 4 and 6 are substantially one-half wave length at the operating frequency. The physical length of these members is somewhat shorter thanone-half wave length but the inherent capacitances between the extremities of the members operate -to make the members 4 and 6 substantially resonant at the operating frequency. These inherent capacitances are represented by the characters I6 and I8.

The antenna 2 is energized from acrossed transmission line 20, the mid-point of which is connected to a coupling coil 22 over a short trans*- mission line 24. The coil 22 is coupled to the oscillatory circuit 26 associated with the oscillation generator 28. The oscillator and associated oscillatory circut may comprise any suitable construction and as disclosed in my above mentioned copending application the oscillation circuit 26 may take the form of a Lecher frame. While I have illustrated the use of inductive coupling, capacitive or other types of coupling could also be employed.' l

The genera-tor andV circuits are enclosed within a container 30. This container should have as small a cross-section as possible consistent with the apparatus which it encloses, and should preferably be substantially one-quarter wave length long. By coupling a portion of the output of the generator to the container 30, as illustrated by the variable coupling capacitor 32, the container itself functions as a radiator of electromagnetic waves. The `polarization of these Waves will be vertical or more properly have a polarization at right angles to the polarization of the waves radiated from the antenna 2.

The antenna system 2 acts substantially as a counterpoise for the container and together with the container should be adjusted to approximately one half wave length. With a given size of antenna system 2, this adjustment is made preferably by properly designing the container for the given frequency of operation. Although` the system may be designed for one particular frequency, it will operate satisfactorily over a considerable band of frequencies due to the relatively large cross-sectional area of the container itself. The entire unit thus provides a repeater with two antennas, one antenna comprising container 30 operating with one polarization while for supplying power to the antenna system. A.

suitable phase shifter represented by the block 56' is shown inserted in the leads 52 between the point 64 and the dipole 54; The phase shifter isA designed to either advanceV or retard the phaseof the current passing into the dipole. ft by- 901 with respect to the phase of the current passing into the dipole 52. This means that the dipole. 52 and 54 are fed by currents in quadrature phase relation with the result that a rotatinghorizontallyI polarized Wave is radiated from the dipoles. vIt is, of course, desirable to so space the leads 6|] and 52 where they make contact with the dipoles 52 and 55. respectively, that a proper impedancey match .exists between the leads and the dipoles. This is common practiceY andforms no part of my invention. y.

In Fig. 2 I haveillustrated thecontainer 58s as substantiallyV circular in cross-section. The actual cross-sectionalV shape ofthe container,

however, is largely optional providedv its` length" is substantially one-quarter wave atrthe operating frequency and its cross-section is relatively small.

The manner in which the container 5B is energized from the generator 5B is illustrated as a variable capacitor coupling: 63. Itis desirable that this capacitance be made adjustable in order that the desiredamount of energy may-be passed tothe. radiating container 58. It is preferable thatthe energy radiated from the crosseddipoles 52 and 54 be substantially equal to that radiated by thev container 58. This is also` true in the case of Fig. lpwhere it is desirable to have the energy radiated by the container 30 substantially equal to` that radiated by the antenna system 2.

In Fig. 2 I have schematically illustrated the `manner in which the antenna system of my invention may be attached-to a balloon 69 by any suitable supporting means. such as suspension cables` 1.0..

2,641,756 i f Y.

While I have described above the principles of my invention in connection with specific apparatus and a particular modification thereof, I recognize that many variations and modifications thereof are possible without departing from the invention. For example, the horizontal antenna instead of the vertical antenna may be so constructed as toenclose the oscillating generator. It will be' understood, therefore, that this description is made only by way of example and not as a. limitation on the scope of my invention as set forth in the objects of my invention and the accompanying claims.

I claim; 1.. In combination, a radiator adapted to radiate substantially horizontally polarized waves, an oscillation generator, said generatorbeing connectedl to saidv radiator for energizing same, and a container enclosing said generator, said container being electrically'connected to said radiator yand together therewith being adapted to radiater vertically polarized waves.- l Y 2. The combination in accordance-with claim 1 wherein said container is so-shaped that itslength is relatively long with respect to its. width,r said length being substantially equal to one fourth wave length. i Y

3. In combination,` a rst antennaadapted to radiate waves having a given polarization, a sec.- ond antennar adapted to radiate waves having a polarization which is at right angles to the waves radiated by .said rst antenna, an impulse repeater, one of said antennas being in .theform of a. hollow conductor, said. repeater. being `positioned within said one or" said antennas', and circuit connections whereby energy isinterchanged between said antennas and said generator.

SVEN H.. nombraron'.

Referenees cited inv the nie of this. patent UNITED STATES PATENTS y Number Name Date 1,930,505. Brown Oct. 1'7", 1933 2,093,432- Gordonl L Sept. 2'1, 1937 2,169,358 Hollmann Aug; 15, 1939 2,180,855 Wundt etal...v Nov. 2l, 1939 2,234,333- Brown et al, Mar- 11'., 1941 2,267,889 Aubertl Dec. 30,194.1 

